Capture Fox is free and nice utility that allows you to record screencasting right from your Firefox browser.Even Firefox has tons of add-ons like Abduction that let you capture screenshots from your Firefox browser but the CaptureFox have moved one step further and provides you a platform to record your Desktop Screencast along with your voice & you can save the output file as Video file format.

It allows you to record whole screen or firefox screen depending on your needs.If you wish to make video based on windows software tutorial you can select Whole screen or if you want to show any tutorial based on Internet or browser, you may go for Firefox window.You can manually set the Video quality as low, moderate to High & even set the Frames per second that is most necessary while capturing video.If you want to add voice narration while capturing your video, you may tick mark the voice recording option otherwise leave it blank.You can even customize the output folder and by hitting the start capturing button you will be able to record your Screencast with just a Firefox add-ons only.

In advance setting you can choose Video Codec in JPEG or XVID & audio coded as WAV or MP3 file format.
[update: It is currently supported to Firefox 5 and Firefox 6 version only.]